There are known radio frequency (RF) tags also called electronic labels or communication beacons provided with a communication circuit. This type of communication circuit comprises an antenna connected to a modulation/demodulation stage for processing an incoming signal or an outgoing signal. Such an RF tag is also provided with a power supply system, i.e. a stage that uses the energy received on reception of a signal to supply the entire RF tag with electrical energy.
This type of stage generally includes an AC/DC converter converting a received alternating signal into a continuous power signal. An AC/DC converter of this type takes the form, for example, of a diode bridge of the Graetz type.
However, depending on the type of incoming signals, it is necessary to have an AC/DC converter able to work not only at low power but also at high power.
Further, one problem of AC/DC converters is that they may have stray capacitances. Indeed, each antenna operates in an optimum manner with a tuning capacitor. It is therefore sought to control the value of the tuning capacitor associated with the antenna and therefore to reduce the value of stray capacitances so that they do not significantly disrupt the desired antenna characteristic. Therefore, as the AC/DC converter is the largest contributor to stray capacitances, it is important to select assemblies that minimise stray capacitance contribution.
Further, RF tags face a risk of the AC/DC converter being destroyed subsequent to excessively high voltage in the AC/DC converter, which causes damage to the components. A known solution is to clip the signal beyond a predetermined voltage value. However, one drawback of clipping the input signal is that it distorts the signal resulting in a loss of information.